It’s time for another batch of startups to show off what they’ve got. It’s Y Combinator’s demo day, and over the past two days, 104 companies have presented their services, devices, technology, and promise. Will one of these companies become the next Stripe? Dropbox? Airbnb? Or a potential unicorn?

These two days saw presentations from startup after startup, on topics ranging from marijuana to education, ecommerce to biotech. There were some great presentations, but did any really stand out?

Because of the sheer number of startups participating in Y Combinator’s summer 2015 batch, they were divided up into two different groups. The first day focused on startups within the enterprise, biomedical, hardware, and fintech spaces, while the second day featured those pursuing the consumer, business-to-business, developer tools, marketplaces, and nonprofits sectors.

Here’s a roundup of the 11 that were perhaps the most notable from this season’s batch (in order of presentation):

Oolu

Oolu focuses on helping people in West Africa tap into solar power to provide lighting and charge cell phones more conveniently and at a fraction of the standard price. The company says that there are 150 million people in the region living without electricity and often relying on flashlights, candles, or kerosene. Oolu leases a solar home system of three lights and two cell phone chargers for just $6 per month. This is much cheaper than the $14 per month families would typically have to pay for electricity.

To date, the company has 1,350 paying customers with an additional 2,000 on the waiting list.